Retinol, alpha-tocopherol, beta-carotene, and perhaps other carotenoids all appear to have possible cancer chemopreventive effects in either in vitro or epidemiological studies (based on dietary history or serological data). However, blood levels of these micronutrients may be less important than tissue levels in predicting cancer chemopreventive effects. In this application, we propose to develop analytical methods for measuring tissue content of these micronutrients. We will then examine the relation between blood and tissue levels of these micronutrients within patients, and compare tissue levels of these micronutrients in patients with and without cancer. The specific aims are: 1. To develop and verify analytical methods for simultaneously measuring plasma and tissue levels of retinol, alpha-tocopherol, and multiple carotenoids. 2. To examine the relation between micronutrient levels in plasma, nonmalignant tissue, and malignant tissue in cancer patients with nonmelanoma skin cancer, colon cancer, breast cancer, and lung cancer. 3. To examine the relation between micronutrient levels in plasma and nonmalignant tissue in control patients undergoing surgical procedures for noncancerous skin conditions, nonmalignant colonic lesions, nonmalignant breast lesions, and non-malignant lung lesions. 4. Using the data from the cancer and control patients outlined above, to examine the relative importance of the presence of cancer and other personal factors (e.g. age, sex, dietary history, smoking status, etc.) upon the relation between serum and tissue levels of these micronutrients. 5. In a limited number of patients, to examine the effects of oral supplementation with beta-carotene or oral alpha-tocopherol upon the relation between plasma and tissue levels of these micronutrients.